Fitbit Fitbit Versa Lite Smartwatchsells on Amazon for what I think is a very good price. Please read some of the reviews and see people thought of the product. Also please check if you might qualify for a free shipping offer if available.

Track your all-day activity, 24/7 heart rate, & sleep stages — all with a 4+ day battery life (varies with use and other factors)

Use 15+ exercise modes like Run or Swim (Fitbit Versa is water-resistant to 50 meters) to record workouts and connect to smartphone GPS for more precise real-time pace & distance